Operation principle of Ethereum DAPP
just like bitcoin, Ethereum is neither controlled nor owned by anyone - it is an open source project created by many people around the world. Different from bitcoin protocol, Ethereum's design is very flexible and adaptable. It is very easy to create new applications on the Ethereum platform. With the release of homestead, anyone can use the applications on this platform safely
Ethereum is a programmable blockchain. It does not give users a series of preset operations, but allows users to create complex operations according to their own wishes. In this way, it can be used as a platform for many types of decentralized blockchain applications
in a narrow sense, Ethereum refers to a series of protocols that define a decentralized application platform. The core of Ethereum is Ethereum virtual machine (EVM), which can encode any complex algorithm. In computer science terminology, Ethereum is "Turing complete.". Developers can use the existing JavaScript and python as the model of other friendly programming languages to create applications running on the Ethereum simulator.
Ethereum is a new and open blockchain platform, which allows anyone to build and use decentralized applications running through blockchain technology in the platform. Like bitcoin, Ethereum is neither controlled nor owned by anyone - it's an open source project created by many people around the world
Different from bitcoin protocol, Ethereum is very flexible and adaptable. It's very easy to create new applications on the Ethereum platform. Anyone can use the applications on the platform safely 
Ethereum is a programmable blockchain. It does not give users a series of preset operations (such as bitcoin trading), but allows users to create complex operations according to their own wishes. In this way, it can be used as a platform for many types of decentralized blockchain applications, including but not limited to cryptocurrency
in a narrow sense, Ethereum refers to a series of protocols that define a decentralized application platform. The core of Ethereum is Ethereum virtual machine (EVM), which can encode any complex algorithm. In computer science terminology, Ethereum is "Turing complete.". Developers can use the existing JavaScript and python as the model of other friendly programming languages to create applications running on the Ethereum simulator
like other blockchains, Ethereum also has a peer-to-peer network protocol. Ethereum blockchain database is maintained and updated by many nodes connected to the network. Each network node runs the Ethereum simulator and executes the same instructions. Therefore, people sometimes call Ethereum "world computer"
this massive parallel operation throughout the Ethernet network is not to make the operation more efficient. In fact, this process makes computing on Ethereum slower and more expensive than on traditional computers. However, each Ethereum node runs Ethereum virtual machine in order to maintain the consistency of the whole blockchain. The consistency of decentralization makes Ethereum have high fault tolerance, zero downtime, and can keep the data stored on the blockchain unchanged and anti censorship
Ethereum platform has no characteristics and value. Like programming languages, it's up to entrepreneurs and developers to decide what to use. However, it is clear that some application types benefit more from the functions of Ethereum than others. Ethereum is especially suitable for those applications that automatically interact directly between points or promote group coordination activities across networks
for example, coordinate the application of point-to-point market, or the automation of complex financial contracts. Bitcoin enables indivials to exchange money without the help of financial institutions, banks or governments. The impact of Ethereum may be more profound
in theory, any complex financial activities or transactions can be automatically and reliably carried out on Ethereum with coding. In addition to financial applications, any application scenario with high requirements for trust, security and persistence, such as asset registration, voting, management and Internet of things, will be affected by Ethereum platform on a large scale
Ethereum energy coin is not MLM
Ethereum is an open source public blockchain platform with smart contract function. Ethereum provides decentralized virtual machine (Ethereum virtual machine) to process point-to-point contract through its special cryptocurrency Ethereum
in 2013, vitalik buterin, 19, first mentioned the idea of Ethereum in a book entitled "Ethereum white paper: next generation intelligent connection and decentralized application platform". Then, in 2014, the algorithm and protocol of Ethernet coin were officially implemented, and $150 million was raised. The system itself was finally completed on July 30, 2015
as the representative of blockchain 2.0, the mainstream currency Ethernet is regarded as the wind vane of crypto digital currency market. However, over the past week, the price of ether currency has continued to fall. On August 14, 2018, the ethereal currency plummeted by 20%, reaching a record low of $257 this year. Compared with this year's peak of $1295, the price of Ethernet currency has shrunk by more than 80%. Affected by this, on August 15, 2018, none of the top ten mainstream currencies in the digital money market was spared, falling across the board, with a number of single day declines exceeding 10%
extended data
Ethereum started planning almost in 2013, and started to implement the project in 2015. Before that, there were many digital currencies imitating bitcoin in the market, and they made various modifications on the basis of bitcoin code. In this way, it is very difficult to develop a new blockchain application, to re deploy a new chain, and then to develop an application on this chain. Using a consensus mechanism of pow alone is a huge maintenance workload. It's like developing an app on a mobile phone and developing the Android system together
after Ethereum comes out, it is equivalent to the underlying operating system of the blockchain. On Ethereum, it is very convenient to develop various dapps without considering the underlying development, and it can also share the computing power and storage of Ethereum. For programmers, the threshold of blockchain development is lowered instantly. The emergence of Ethereum has played a very important role in the development and popularization of blockchain applications. That's why Ethereum is called blockchain 2.0
do you remember what the consensus mechanism of bitcoin is? The consensus mechanism of bitcoin is pow. To put it simply, the more work you do, the higher the amount of computation you pay, the more likely you will be the first to find the correct hash value, and the more likely you will be rewarded with bitcoin
however, there are some defects in the pow of bitcoin, that is, it is too slow to process transactions, and miners need to constantly collide hash values through calculation, which is costly and inefficient. Friends who are interested in blockchain knowledge should see such a saying:
in order to make up for the deficiency of bitcoin, Ethereum has proposed a new consensus mechanism, called POS (this is the abbreviation of English, which means "proof of equity", also translated into "proof of equity")
POS simply means the same as its literal meaning: equity, equity. The more currency you hold, the more equity you have, the higher your equity
Ethereum's POS means that the more money you hold, the longer you hold it, the less difficult it will be to calculate and the easier it will be to mine
in the initial setting of Ethereum, Ethereum hopes to build a relatively stable system by using POW in the early stage, then graally adopt POW + POS, and finally completely transition to POS. So, it's true that the consensus mechanism of Ethereum is POS, but POS is only a plan or goal at the beginning of Ethereum's release. At present, Ethereum has not yet transitioned to POS, and the consensus mechanism adopted by Ethereum is still pow, that is, the pow of bitcoin, but it is slightly different from the pow of bitcoin
the amount of information here is a bit large,
the first information point is that the consensus mechanism currently adopted by Ethereum is also pow, but it is slightly different from the pow of bitcoin. So, what's the difference between the pow of Ethereum and bitcoin: in short, the mining difficulty of Ethereum can be adjusted, but the mining difficulty of bitcoin can't be adjusted. Just like our college entrance examination, because the teaching situation and the number of students in different provinces are not the same, so the college entrance examination is divided into national papers and provincial independent proposition
Ethereum said that I am in favor of the topic by region. Bitcoin said: No, it must be the same volume in the whole country. The difficulty is the same for everyone
the popular explanation is that bitcoin uses computer computing power to do a lot of hash collisions, enumerate various possibilities to find a correct hash value. The Ethereum system has a special formula to calculate the difficulty of each block. If a block is verified faster than the previous block, Ethereum protocol will increase the difficulty of the block. By adjusting the block difficulty, the time needed to verify the block can be adjusted
according to the Ethereum protocol, the dynamic adjustment method of difficulty is to make the time interval of creating new blocks in the whole network 15 seconds, and the network uses 15 seconds to create blockchain. In this way, because the time is too fast, the synchronization of the system is greatly improved, and it is difficult for malicious participants to launch 51% (that is, more than half) of the computing power to modify historical data in such a short time
the second information point is: in the initial setting of Ethereum, we hope to achieve the transition from POW to
POS through phased upgrade
dating back to 2014, at the beginning of Ethereum's launch, the team announced that the launch of the project would be divided into four stages, namely, Froniter, homestead, metropolis and serenity. In the first three stages, the consensus mechanism adopts pow (workload proof mechanism), and in the fourth stage, it switches to POS (equity proof mechanism)
on July 30, 2015, the first phase "frontier" of Ethereum was officially released. This phase is only suitable for developers. Developers can write smart contracts and decentralized application DAPP on Ethereum network, and miners begin to enter Ethereum network to maintain network security and get Ethereum coins. The leading-edge version is similar to the beta version, proving whether the Ethereum network is reliable or not
on March 14, 2016, Ethereum entered the second stage of "homeland". In this stage, Ethereum provides the wallet function, so that ordinary users can easily experience and use Ethereum. There is no obvious technology improvement in other aspects, but it shows that Ethereum network can run smoothly
in September 2017, Ethereum has reached the third stage of "metropolis"“ "Metropolis" is composed of Byzantine and Constantinople. The goal of this stage is to introce the hybrid chain mode of POW and POS, so as to prepare for the smooth transition from POW to POS. This is the latest popular "Ethereum Constantinople upgrade". In the Constantinople upgrade, Ethereum will make some changes to the underlying protocols and algorithms to lay a good foundation for the implementation of POW and
POS
how much reward will Ethereum get for mining? Miners who win the block creation competition will get the following income:
1. Static reward, 5 ethereums
2. The fuel cost in the block, i.e. gas, we talked about in the last issue
3. As a part of the block, it includes the extra reward of "Uncle block". Uncle is uncle of uncle, and each uncle block can get 1 / 32 of the mining reward as a reward, that is, 5 times 1 / 32, which is equal to 0.15625 ethereums. Here, let's briefly explain the concept of "TERT block". The concept of "TERT block" was proposed by Ethereum. Why should we introce the concept of TERT block? This also starts with bitcoin. In the bitcoin protocol, the longest chain is considered absolutely correct. If a block is not part of the longest chain, it is called a "orphan block". An isolated block is a block, which is also legal, but it may be found later, or the network transmission is slower, and it does not become part of the longest chain. In bitcoin, the solitude is meaningless and will be discarded later, and the miners who find the solitude will not receive mining related rewards
however, Ethereum does not think that isolated blocks are worthless, and Ethereum system will give rewards to miners who find isolated blocks. In Ethereum, isolated blocks are called "Uncle blocks", which can contribute to the security of the main chain. Ethereum's ten second block interval is too fast, which will rece the security. By encouraging the use of tertiary blocks, the main chain can obtain more security guarantees (because the isolated block itself is legal). Moreover, paying the tertiary block can also stimulate the miners to actively mine and actively use tertiary blocks. Therefore, Ethereum thinks that it is valuable.
DAPP is an Internet application. The biggest difference between DAPP and traditional app is that DAPP runs on a decentralized network, that is, a blockchain network. There is no centralized node in the network, which can control DAPP completely. As we all know, app is centralized. Need to request a server to get data, process data, etc
compared with DAPP, blockchain is the underlying environment for application running. It can be compared to IOS, andorid and other mobile operating systems running on various apps. Learning blockchain is not the bottom part of learning blockchain. Maybe more people need to learn the development of DAPP. Build and run applications in the blockchain environment< br />
a complete DAPP needs to meet the requirements of completely open source and autonomous applications. DAPP cannot be changed once it is deployed. The upgrade of the application can only be carried out after most users reach a consensus. All data must be encrypted and stored on the decentralized blockchain application platform. Secondly, DAPP must have token mechanism
DAPP can be fault-tolerant without single point of failure. They don't have centralized institutions to interfere. There will be no deletion or modification of some data. It can't even be shut down. Because the data is encrypted storage, there will be no user data leakage events like Facebook and Google
of course, at present, most DAPP procts are still in the experimental stage. Although blockchain technology has brought us a lot of imagination, the specific implementation of DAPP procts still needs to consider a lot of relevant factors.
DAPP is the abbreviation of Chinese distributed app for decentralized application
a DAPP has background code running in a distributed peer-to-peer network. The background code of traditional app is running on the centralized server
the front-end code of a DAPP can be developed by any language, just like the traditional app. In addition, DAPP's front-end code can be hosted in distributed storage services, such as swarm or IPFs
If an application = front end + back end, because Ethereum contract is composed of code running in Ethereum distributed point-to-point network, distributed application = front end + contract
the picture shows a DAPP architecture:
app we all know that it is a client application, which is the abbreviation of application. DAPP is d + app, and D is the first letter of English word decentralization. Chinese word translation is decentralization, that is DAPP is decentralized application. This is to understand the concept literally. To form a clear, accurate and necessary concept in the brain, we need to understand DAPP in depth
compared with app, the biggest difference between them is centralization and decentralization. App needs money first, so it needs financing first; Then there will be more people, so we will develop and operate after recruiting all the people. DAPP is the proct of inheriting traditional app and combining the characteristics of blockchain, which is more like crowdfunding mode, sharing mode and decentralization mode